David John Moore Cornwell began writing novels about espionage and spies when he was working as a full-time intelligence agent for the British foreign service MI6 – a group whose very existence was not acknowledged by the British government until 1994. He wrote under the pen name John le Carré (“John the Square” in French) only because foreign intelligence service were forbidden to publish under their own names. When his third novel The Spy Who Came in from the Cold (1963) became an international best-seller, he left MI6 to become a full-time author, but obviously part of him has always stayed in the intelligence services – for all of his books concern themselves with secrets, lies, espionage and spycraft. I’ve enjoyed reading John le Carré from time to...